A wide range of normal and pathological conditions can alter the blood and oxygen supply to body tissue. Such conditions can be systemic, affecting the whole body, or localized, affecting a portion of the body, i.e., a particular region or organ(s) of the body. Such conditions can relate to the hemoglobin content of the blood, respiratory function, metabolic demand of the particular body tissue, and pathological conditions or diseases such as heart failure, hypertension, diabetes, vascular disease, etc.
Bedside monitoring devices are available for measuring the oxygen saturation of the blood, e.g., pulse oximeters, or a localized area of tissue. However, a need remains for improved sensors and methods for monitoring the oxygenation status of body tissue for tracking patient status and managing and optimizing therapies.